In recent years, the quantity of thermoplastic and elastomeric materials used in automobile manufacture has increased markedly. For example, such polymeric materials have been used increasing as exterior body components, and, with the installation of increasingly complex bumper systems, sight shields have been incorporated between the main body components and the bumpers. A concurrent need has arisen for enamel coatings which are compatible with the thermoplastic and elastomeric materials. Such coatings, in their finished state, should be hard, since hard coatings tend to stay cleaner, retain their gloss and resist scratching. At the same time, in the use of enamels on polymeric substrates, a flexibility is needed which typically has heretofore been provided only through a significant reduction in hardness.